Several different methods and arrangements of the aforesaid nature and intended for the aforesaid application are known to the art.
By way of a first example of the background art and the technical field to which the present invention relates can be mentioned the possibility of constructing a requisite gas cell with an associated cavity having light reflecting wall portions as a separate unit and mounting this unit on a circuit board or on one surface of a surface-mounted circuit board, with the electronic circuits of a control unit being more or less related or a printed circuit board or to a surface-mounted circuit board.
It is also known to mount the light source and/or the light detector on one surface of a printed circuit board or of a surface-mounted circuit board and to form the gas cell with its cavity as a discrete component and to place this component between the light source and the light detector.
Also known to the prior art technology is a controlling and computing unit which includes a number of processor-controlled electronic circuits for executing a number of functions, among others the function of assessing the presence of and/or the concentration of a gas and/or a gas consistency by virtue of the wavelength and/or wavelengths of said gas absorbed during its passage through a measuring path in the cell in response to a signal structure obtained via the light detector in response to a generated pulsated light structure initiated via the light emitter.
Also belonging to the technology, to which the present invention relates, is an arrangement, taught by International Patent Publication WO-A1-01/81900.
This prior publication teaches an arrangement which is intended to be surface mounted on a printed circuit board or so-called surface-mounted board, where requisite circuit arrangements can be coordinated with surface mounted circuits and components.
As a part of the prior art, to be considered, is shown and described in the European Patent Application Serial Number 94 1 207 993.8 (EP-A2-0 704 691).
This patent publication discloses an Infra-Red Spectrometer Sensor for gases using micro-structure reflecting surfaces.